Solution of resins and the process of manufacturing same.



UNITED s'rArr s PATENT OFFICE.

ALBERT HESSE, OF WILMERSDORF, GERMANY.

SOLUTION OF RESINS AND THE PROCESS OF MANUFACIURING'SAME.

Specification of Letters Patent.

i No Drawing Originalapplication filed June 13, 1910, Serial No.566,673. Divided and this application filed March 4. 1911.

' 1'0 all whom it may concern:

llc it known that I, ALBERT Hnssu, a subect. ot the German Emperor, andresident ot'TWIlmersdorf, m the Kingdom of Prus- -sia. German Empire,haveinvented new i and useful Imwovemcnts in Solutions of Resins and inthe Process of Manufacturing 1 I t b I n i I bame, o't which the:tollowmg 1s a lull, clear, and exact specification.

In my apphcatlon filed June 13th, 1910, Scr. No. 566,673 ot which thisis a divisional application, I have shown that the alkyl and aryl estersof phthalic acid, wluch have I hitherto only been described in Pientificliterature, are of great technical interest since they are excellentsolvents for odorrferous substances. I have further found that theseesters can dissolve also resins and each other or with other solvents,whereby thesolvent capacity of the latter is in many cases enhanced.

P The use of phthalic acid esters as a solvent for resins is especiallyvaluable for the followingreasons; In many cases, for i'nstance inpreparing copal-varnishes, it 'is necessary to subject the copal resinto a heating operation in order to bring about certain decompositionswhich are necessary to nnpart to the product certain propertiesrequisite for its technical application. The

high temperature, however. 1s accompanied' by the disadvantage that inaddition to the desired decomposition, undesirable secondary changesoccur which injuriously affect 'the properties, for instance impart tothe product a dark color. The use of the afore- .said phthalic acidesters as solvents avoids this disadvantage. By heating the resindissolved in one of theesters, instead of b melting it, the secondarychanges are avoi ed. It is particularly advantageous that Serial No.612,403.

by selection of one of said esters or mixture of the same, thetemperature required can be attained at ordinary pressure and can beadjusted within very wide limits depending upon the boiling point of thesolvent and the concentration of the solution.

Emamples.

1. 1 part of colophony is heated with 0.3 parts of phthalic aciddimethyl ester or diethyl ester, a perfectly clear solution beingformed. A larger proportion of the sol vent is necessary if the solutionis to remain clear on cooling. This, however, is not necessary for themost technical purposes.

2. 100 kilograms of copal resin are heated with 100 kilograms ofdiethylphthalate until the water and the ethereal oil which are formedby the decomposition of the resin are distilled oil". This solution 'canbe used, as such or after a part ofthe diethylphthalate has beendistilled off, for preparing varnishes and for all other pu.,)oses .for"

4. As a new composition of matter a solu-- j tion of'a resin containinga phthalic acid ester as a solvent.

5. As a new composition of matter a solution of copal resin, containinga phthallc acid ester ias a solvent.

In testimony, that I claim the foregoing as niyinventioh, I have signedmy name in presence of two subscribing witnesses.

ALBERT HESSE. Witnesses:

WOLDEMAR HAUPr, Henry HASPER.

